Enhancing Butadiene Yield and Catalyst Stability via Aqueous Feed Dilution in 1,3-Butanediol Dehydration

Abstract

The influence of using water as a diluent on the catalytic performance and deactivation in the gas-phase reaction of 1,3-butanediol (1,3BDOL) at 523 K was studied on four solid acid catalysts: HZSM5, SiO₂/Al₂O₃, Al₂O₃, and TPA (tungstophosphoric acid)/SiO₂. Reactions were carried out using both pure 1,3BDOL and 1,3BDOL 10 wt% in water as reactants. Both fresh and spent catalysts were characterized using various techniques, including N₂ physisorption, Fourier Transform Infrared (FTIR) spectroscopy, FTIR of adsorbed pyridine, MAS NMR, and Temperature Programmed Oxidation (TPO). The use of 1,3-butanediol diluted in water in the reaction increased butadiene selectivity over SiO₂/Al₂O₃, HZSM5, and TPA/SiO₂ while reducing coke formation, without altering the nature of the carbonaceous deposits, as confirmed by TPO and FTIR analyses. The reaction results showed that the presence of water is a key parameter in mitigating deactivation, enhancing the stability of catalytic activity during the conversion of 1,3BDOL on SiO₂/Al₂O₃, HZSM5, and TPA/SiO₂, as well as the selectivity towards butadiene.